Harlequin Rasbora and Otocinclus Compatibility Overview
Harlequin Rasbora and Otocinclus can generally share an aquarium with appropriate planning. Both species prefer overlapping temperature and pH ranges. Both species are peaceful, and neither poses a major aggression risk to the other. A minimum 20-gallon tank is recommended to provide adequate territory and water volume for both species.
| Factor | Harlequin Rasbora | Otocinclus | Verdict |
|---|---|---|---|
| Temperature | 72โ81ยฐF | 72โ82ยฐF | โ 72โ81ยฐF |
| pH Range | 5.5โ7.5 | 6.0โ7.5 | โ 6.0โ7.5 |
| Temperament | peaceful | peaceful | โ Compatible |
| Adult Size | 1.75 in | 1.5 in | โ Similar |
| Min. Group | 8+ | 4+ | See below |
| Min. Tank Size | 20 gallons (for both species) | โ | |
Compatibility Positives
Caution Points
Species Profiles
Harlequin Rasbora โ Trigonostigma heteromorpha
Active mid-level schooling fish with a distinctive black triangular patch. One of the best all-around community tank fish.
โ Full Harlequin Rasbora care guide
Otocinclus โ Otocinclus spp.
Tiny algae-eating catfish that are peaceful with all species. Need established algae growth and biofilm; sensitive to ammonia.
Frequently Asked Questions
Can Harlequin Rasbora live with Otocinclus?
Yes, in a well-planned setup. Harlequin Rasbora and Otocinclus can generally share an aquarium with appropriate planning. Both species prefer overlapping temperature and pH ranges. Both species are peaceful, and neither poses a major aggression risk to the other. A minimum 20-gallon tank is recommended to provide adequate territory and water volume for both species.
What tank size do I need for Harlequin Rasbora and Otocinclus together?
A minimum of 20 gallons is recommended for keeping Harlequin Rasbora and Otocinclus together. A larger tank improves water stability and reduces territorial conflict.
What temperature suits both Harlequin Rasbora and Otocinclus?
72โ81ยฐF โ inside Harlequin Rasbora's 72โ81ยฐF and Otocinclus's 72โ82ยฐF.
Is a Harlequin Rasbora aggressive toward a Otocinclus?
Harlequin Rasbora is peaceful and Otocinclus is peaceful. No major aggression issues are expected between these species.
Related Compatibility Guides
Tank Size for Harlequin Rasbora and Otocinclus
Use the scenario that matches the actual group sizes and temperament you plan to keep.
| Scenario | Tank | When it applies |
|---|---|---|
| Minimum viable | 20 gal | Only for the recommended minimum groups, mature filtration, and close monitoring. |
| Recommended community | 29 gal | Adds territory, swimming room, and a safer buffer for behavior. |
| Low-conflict setup | 55 gal | Best when keeping larger schools or reducing territorial pressure. |